This invention relates to a control to selectively operate a heating system including a solar heating system.
Various controls have been employed to operate solar heating systems which selectively operate to transfer fluid from a collector to one or more areas to provide heat energy. Some systems directly supply fluid from a collector to an enclosure such as a home, building or other structure or, alternatively, conduct fluid from the collector to a storage area for retention for possible future use. Other systems conduct fluid from a collector to a transducer for heating water to provide a hot water supply for various uses. While some systems have operated independently to conduct fluid from a collector to an enclosure, from a collector to a storage area, from a collector to a hot water system or from a storage area to an enclosure, other systems have been commonly controlled to coordinate the fluid flow between such various components to provide a system operation.
A solar heating system is frequently added to a previously existent auxiliary heating system, such as a furnace or a heat pump for example, which have been connected to operate in response to an environmental sensor located at a particular area designed to receive heated fluid, such as within an enclosure for example. When such a solar heating system is interfaced with a pre-existent auxiliary heating system, extensive modifications of the existing heating system have been frequently required to permit interaction between the solar and auxiliary heating systems. In some cases, the existent environmental sensor is required to be replaced while, in other instances, two environmental sensors are required with one connected to operate the solar heating system and the other connected to operate the auxiliary heating system. In cases where a single environmental sensor is employed for commanding the operation of both the solar and auxiliary heating systems, an electrical control intervenes to intercept the command signal and in turn, generate a second signal or signals to control the auxiliary heating system and the solar heating system. Such construction has caused problems in the proper operation of an anticipator circuit provided within the environmental sensor which customarily operates to provide a range of cyclic operation in response to varying environmental conditions.
Some control systems have been extremely sensitive to external environmental transient conditions which may lead to spurious operations or might otherwise damage the control under severe externally generated conditions.